I´m kind of new at this so I´m trying some simple examples, when I place a "file" node, I select a data file and then I connect it to a "visualize" node such as scatter plot or Attribute Statistics, I get the following in the Output window. Is this some kind of bug or am I doing something wrong?

It seems to be a bug, but I can't duplicate it.Which version of PyQt4 do you have installed (you can check the version in the windows control panel)? The one that came with the orange installer or did you install a different version?